.\" Copyright (c) 1993
.\"	The Regents of the University of California.  All rights reserved.
.\"
.\" This code is derived from software contributed to Berkeley by
.\" Donn Seeley at BSDI.
.\"
.\" Redistribution and use in source and binary forms, with or without
.\" modification, are permitted provided that the following conditions
.\" are met:
.\" 1. Redistributions of source code must retain the above copyright
.\"    notice, this list of conditions and the following disclaimer.
.\" 2. Redistributions in binary form must reproduce the above copyright
.\"    notice, this list of conditions and the following disclaimer in the
.\"    documentation and/or other materials provided with the distribution.
.\" 4. Neither the name of the University nor the names of its contributors
.\"    may be used to endorse or promote products derived from this software
.\"    without specific prior written permission.
.\"
.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
.\" ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
.\" SUCH DAMAGE.
.\"
.\"	@(#)setlocale.3	8.1 (Berkeley) 6/9/93
.\" $FreeBSD$
.\"
.Dd November 21, 2003
.Dt SETLOCALE 3
.Os
.Sh NAME
.Nm setlocale
.Nd natural language formatting for C
.Sh LIBRARY
.Lb libc
.Sh SYNOPSIS
.In locale.h
.Ft char *
.Fo setlocale
.Fa "int category"
.Fa "const char *locale"
.Fc
.Sh DESCRIPTION
The
.Fn setlocale
function sets the C library's notion
of natural language formatting style
for particular sets of routines.
Each such style is called a
.Sq locale
and is invoked using an appropriate name passed as a C string.
.Pp
The
.Fn setlocale
function recognizes several categories of routines.
These are the categories and the sets of routines they select:
.Bl -tag -width LC_MONETARY
.It Dv LC_ALL
Set the entire locale generically.
.It Dv LC_COLLATE
Set a locale for string collation routines.
This controls alphabetic ordering in
.Fn strcoll
and
.Fn strxfrm .
.It Dv LC_CTYPE
Set a locale for the
.Xr ctype 3
and
.Xr multibyte 3
functions.
This controls recognition of upper and lower case,
alphabetic or non-alphabetic characters,
and so on.
.It Dv LC_MESSAGES
Set a locale for message catalogs, see
.Xr catopen 3
function.
.It Dv LC_MONETARY
Set a locale for formatting monetary values;
this affects the
.Fn localeconv
function.
.It Dv LC_NUMERIC
Set a locale for formatting numbers.
This controls the formatting of decimal points
in input and output of floating point numbers
in functions such as
.Fn printf
and
.Fn scanf ,
as well as values returned by
.Fn localeconv .
.It Dv LC_TIME
Set a locale for formatting dates and times using the
.Fn strftime
function.
.El
.Pp
Only three locales are defined by default:
the empty string
.Li \&"\|"
(which denotes the native environment) and the
.Li \&"C"
and
.Li \&"POSIX"
locales (which denote the C language environment).
A
.Fa locale
argument of
.Dv NULL
causes
.Fn setlocale
to return the current locale.  An argument of
.Li \&"\|"
will determine the name of the new locale taking into account the environment
variables LANG and LC_*.  If these environment variables yield a locale that is
invalid, NULL will be returned and the current locale will remain unchanged.
By default, C programs start in the
.Li \&"C"
locale.
The only function in the library that sets the locale is
.Fn setlocale ;
the locale is never changed as a side effect of some other routine.
.Sh RETURN VALUES
Upon successful completion,
.Fn setlocale
returns the string associated with the specified
.Fa category
for the requested
.Fa locale .
The
.Fn setlocale
function returns
.Dv NULL
and fails to change the locale
if the given combination of
.Fa category
and
.Fa locale
makes no sense.
.Sh FILES
.Bl -tag -width /usr/share/locale/locale/category -compact
.It Pa $PATH_LOCALE/ Ns Em locale/category
.It Pa /usr/share/locale/ Ns Em locale/category
locale file for the locale
.Em locale
and the category
.Em category .
.It Pa /usr/local/share/locale/ Ns Em locale/category
locale file for the locale
.Em locale
and the category
.Em category .
.El
.Sh ERRORS
No errors are defined.
.Sh SEE ALSO
.Xr colldef 1 ,
.Xr mklocale 1 ,
.Xr catopen 3 ,
.Xr ctype 3 ,
.Xr localeconv 3 ,
.Xr multibyte 3 ,
.Xr strcoll 3 ,
.Xr strxfrm 3 ,
.Xr euc 5 ,
.Xr utf8 5 ,
.Xr environ 7
.Sh STANDARDS
The
.Fn setlocale
function conforms to
.St -isoC-99 .
.Sh HISTORY
The
.Fn setlocale
function first appeared in
.Bx 4.4 .
